1. Field of the Invention
The present invention relates to a touch panel display device, and more particularly relates to a light and slim touch panel display device.
2. Description of Related Art
Touch panel display devices, in which the information data is input by touching with fingers or styli on the display area, are extensively used in personal computers, notebooks, personal digital assistants (PDAs), or other similar devices.
A conventional touch panel display device comprises a display panel and a touch screen attached to the display panel. The touch screen can include at least four technologies, including: capacitive, resistive, surface acoustic wave (SAW), and infrared (optical). As for the general touch screens located in public applications, a capacitive touch screen is often used. With reference to FIG. 1, a conventional touch panel display device is represented, wherein a touch panel display device comprises: a display panel 10 and a touch screen 20. The display panel 10 comprises a CF substrate (color filter substrate) 11, a TFT substrate (thin film transistor substrate) 12, and a LC (liquid crystal) 13 locating between the CF substrate 11 and the TFT substrate 12. A black matrix 111, a plurality of color filter blocks 112, and a transparent electrode layer 113 are located on one side (surface), facing to the TFT substrate 12, of the CF substrate. A polarizing element 114 is located on the other side of the CF substrate. Besides, a touch screen 20 is located next to the polarizing element 114. Herein, the touch screen 20 comprises a substrate 21, and a first conductive layer 22 is selectively formed on one surface of the substrate 21. Then, a second conductive layer 23, a patterned electrode 24, and a passivation layer 25 are sequentially formed on the other surface of the substrate 21. The patterned electrode 24 is located on the periphery of the substrate 21 and electrically connected to the second conductive layer 23, and the passivation layer 25 covers the second conductive layer 23 and the patterned electrode 24. Herein, the substrate 21 may be a glass substrate, and each of the first conductive layer 22 and the second conductive layer 23 may be an ITO (indium tin oxide) layer. Finally, a touch screen 20 is formed on the polarizing element 114 locating on the CF substrate 11, thus a conventional touch panel display device is obtained.
However, in such device having a touch screen on one surface of the display panel, the total weight and total thickness thereof are too great, and is difficult to produce a light and slim touch panel display device. Moreover, the adding of an extra touch screen will decrease the transmittance and lower the brightness of the LCD. Also, the adding of a touch screen on the display panel will increase the cost of the manufacture.